| 초록 |
Two new polymers, which contained methyl-substituted DPP and non-methyl-substituted DPP units respectively, were designed and synthesized. Introducing methyl groups on the thiophene units flanked by DPP core substantially affected their optical, electrochemical and charge transport properties. Experimental results revealed that the introduction of methyl group highered the HOMO and LUMO energy levels of polymers due to the electron donating ability of methyl group. Interestingly, both polymers exhibited terrace morphology which had been rarely observed in DPP-based polymers. In particular, the methyl-substituted PMDPP-Se showed changed phase transition behavior in their thin film morphologies and crystalline structure depending on various temperature conditions, which induced a M-shape temperature dependence of their hole mobility. As a result, the maximum mobility of 1.61 cm2V-1s-1 was achieved in PMDPP-Se (at 300 ℃), while that of PDPP-Se was 1.148 cm2V-1s-1 (at 175 ℃). |
